1. Field of the Invention
This Invention pertains to a bed patient monitoring system and more particularly to a system for detecting the undesired movement of a bed-restricted patient and providing a system of alarms to facilitate returning the patient to a proper position in the bed.
2. Background of the Invention
It is often desirable to restrict patients to their beds and not permit their movement from the bed without supervision of medical personnel or, in many instances, without the direct aid and assistance of such personnel. With the increase of litigation and legal liability in the area of medical care, the consequences of bed-restricted patients getting out of their beds and then being injured, or worsening their condition as a result thereof, is of major economic significance in the health care field. As a result of this and related problems concerning bed-restricted patients, a need has developed to monitor the activity of such patients and to be forewarned that the patient is about to or is trying to leave their bed. One such attempt to solve this problem is set forth in U.S. Pat. No. 4,179,692 issued Dec. 18, 1979, to Dwight A. Vance and entitled "APPARATUS TO INDICATE WHEN A PATIENT HAS EVACUATED A BED OR DEMONSTRATES A RESTLESS CONDITION". The system disclosed in the Vance patent utilizes a variety of switches for detecting patient movement and/or restlessness. The system is arranged to detect the movements of a patient and thereafter try to determine a level of restlessness which when exceeded will indicate that the patient may be getting ready to leave the bed. This and other systems which have attempted to solve this problem have had a variety of shortcomings which are overcome in the present system. If a patient is adjusting themselves in the bed and activates a detecting device which is indicative of an undesirable movement, but in fact the patient is not moving from the bed and resumes a more normal position which would not activate the detecting device, an alarm which may have been activated oftentimes continues to operate even if the patient's activity has ceased.
Other systems do not interface with the nurses' call light which is stationed in the hall over the patient's door and at the nurses' station; or if the systems do interface, they do not differentiate between a patient call and a patient trying to leave a bed, the latter condition normally being a much greater emergency than the former under normal circumstances. On the other hand, some systems require that they be interfaced with the nurses' call station system in order to operate. Many of these systems require rather complex procedures for activating or reactivating the system or for resetting the system if it has been activated. It is desirable to have very simple procedures for activating the system so that doctors, nurses, orderlies or the like, or even visitors or family members who are not familiar with the system, will not inadvertently set off the alarm or if they have deactivated the system in order to move a patient from the bed, forget or be prone to avoid activating or resetting the system because of the complexity of the system or because of forgetfulness. It is also important that any alarm device at a remote location have some means for identifying the discreet room number that houses the patient making an undesirable move. Another problem with such prior systems is that a malfunction in the system is not readily detectable and thus the system may not be working and this not be known to the health care staff. Yet another problem is that of the patient having some way to intentionally or unintentionally either disarm the system or trigger a false alarm. In some systems, once an alarm is set off, each bed must be reset.
Although it is the express object of the Vance patent, cited above, to provide and signal a level of restlessness, it is more desirable to know if the patient is moving from a desired condition and yet not set off an alarm which must be reset in the patient's room should the condition return to normal. In some systems the sensor is placed directly beneath the patient or beneath a sheet and because it is easily moved by the patient's movements, can be moved out of its desired position and then produce false alarms because the detector is mispositioned rather than the patient. In some systems the detector, when placed on top of the mattress, becomes contaminated by contact with the patient or the patient's body fluids and as a result must be replaced with each new patient or after each occurrence of suspected contamination.
One such detecting device is shown in U.S. Pat. No. 4,565,910, issued on Jan. 21, 1986, to Musick, et al, and entitled "SWITCH APPARATUS RESPONSIVE TO DISTORTION". This device, because of its construction, must be placed under sheets, bedding or the like on top of the mattress and thus is protected from patient contact or body fluid contact by only thin layers of materials. Hospitals using this product routinely require its replacement with a new detector unit with each patient turnover.
It is therefore an object of the present invention to provide a new and improved bed patient monitoring system which will overcome the drawbacks of the prior systems.